There's this great app that's basically a text reader in disguise of a Bible. Found here, it was created by rewind22x who created it for reading religious text but also knew it could make other books with a little tweaking. The source for his original app with LDS text is provided in his post.

I was getting frustrated of the official Zune HD eReader app that had a limit on books, annoying scrolling bar thing, and no real outside epub support. I'd tried the other Zune HD readers that other people created but they still weren't that great. Best one I found up til now was here by kirarulzz but it was difficult with not making the title too long or getting an error.

I think that this is the best eReader yet. It lacks bookmarks, it needs improved scrolling, and it restarts the Zune after you exit. However, it does have chapters, a nice layout, and subfolders. The chapters are enough of a bookmark, I think but it would be nice for it to start off right in the book when opened.

I created a sort of base template for the eReader. It has two (half completed - I got lazy) Jane Austen books and an HG Wells book on it with background pictures. You can download ithere.

It's a little confusing at first but mostly you just deal with correcting the .xmls and adding plain text to the .txt files.

These are the most important files to get your eReader to work. Fonts are obvious, textures are the background pictures in .png, titles are the chapters of the book, and .xml where it all happens. GameThumbnail.png is the icon for the app. I think the hardest part to remember is what all the .xmls do. It's important to keep the root.xml and authors.xml. The hgwells.xml lead to the sub folder of xml>hgwells>ttm.xml (table of contents) which directs to titles>hgwells>ttm>all the .txts in that folder (ch1.txt...)

-Make sure to remember to put the fonts, titles, and xml files in "copy if newer" and the book .txt files build action needs to be "none".
-Remember to delete .txts that do not exist and remove the links in the .xml that lead to it. (in photo above it would be tmm.xml)

I hope this was helpful and gives the person that created this app more credit. If there are any problems I'll try to answer them the best I can. Thanks for reading!